Win rate vs risk-reward: the math that decides profit
New traders obsess over win rate, assuming a high one means a good strategy. It doesn't. A system that wins 80% of the time can still lose money, and one that wins only 35% can be a goldmine. What matters is how win rate and risk-reward combine into expectancy — the average profit per trade. Here is the math, made simple.
The win-rate trap
Win rate alone tells you nothing about profitability. Imagine a strategy that wins 90% of trades, making $1 each time, but the 10% of losers lose $20 each. Over 100 trades it makes $90 on winners and loses $200 on losers — a net loss, despite a 90% win rate. Conversely, a system winning just 35% but making $4 per winner and losing $1 per loser is very profitable. The number that matters combines both, as our risk-reward ratio guide explains.
The expectancy formula
Expectancy is the average dollar outcome per trade:
expectancyE = (Win% × AvgWin) − (Loss% × AvgLoss)
# 35% win rate, avg win $4, avg loss $1:
E = (0.35 × 4) − (0.65 × 1) = 1.40 − 0.65 = +0.75 # profitable
Any strategy with positive expectancy makes money over enough trades; any with negative expectancy loses, no matter how good the win rate looks. You can compute yours with the win-rate profit calculator.
The trade-off between the two
Win rate and risk-reward usually pull against each other. Strategies that aim for big winners (high risk-reward) tend to have low win rates — most trades hit the stop while a few run far, the profile of breakout and trend-following systems. Strategies with high win rates usually take small profits and risk larger losses, the profile of mean reversion and grids. Neither is inherently better; both can have positive expectancy.
Applying it to a bot
When you backtest, never judge a strategy by win rate alone — always look at expectancy and the full drawdown. A high-win-rate system with rare giant losses can have a terrible drawdown that wipes you out before the math averages out. Run your rules in the backtester and confirm positive expectancy over a large sample, not a lucky streak.
Frequently asked questions
Is a high win rate good?
Not necessarily. A 90% win rate can still lose money if the rare losers are far bigger than the frequent winners. What matters is expectancy — average profit per trade — which combines win rate with the size of wins and losses.
What win rate do I need to be profitable?
It depends entirely on your risk-reward. With a 3:1 reward-to-risk ratio, you can be profitable winning under 30% of trades. With a 1:2 ratio you need to win over 67%. There is no single profitable win rate.
What is trading expectancy?
Expectancy is the average dollar result per trade: (Win% × average win) − (Loss% × average loss). Positive expectancy means the strategy makes money over enough trades; negative means it loses regardless of win rate.
Should I aim for high win rate or high risk-reward?
Either can work — they usually trade off against each other. Trend and breakout systems have low win rates but large winners; mean-reversion systems win often but risk larger losses. Choose based on expectancy and the drawdown you can tolerate.